Printers, scanners or other printing devices commonly employ a roller/print cylinder to support, or provide a rigid backing structure for the substrate material which carries the printed message/image. The backing structure generally serves to lay the substrate material locally orthogonal and/or at an appropriate distance from the print head/nozzle of the printer. Generally, irregularities in the print surface degrade the efficacy of the printed message/image, i.e., resulting in smearing, smudging, gaps or other undesirable print characteristics.
Envelopes for mailing purposes present unique challenges and anomalies which may be addressed before or after an envelope has been filled or fabricated. It will generally be appreciated that printing prior to envelope filling is most likely to yield a flat/planar surface for optimum printing conditions. That is, an envelope can be viewed as having a print surface comprising multiple layers (a stack having at least two layers when considering the top and bottom face sheets of the envelope) and is best suited for printing before internal contents add other layers or create surface irregularities/anomalies due to an internal staple, clip or binding element.
While certain information such as the mailing address may be pre-printed on an envelope prior to the insertion of mailpiece content material, other information such as the postage indicia should desirably be printed subsequent to mailpiece fabrication. That is, since postage indicia is oftentimes based upon the weight, size and/or thickness of a mailpiece, the postage indicia, which typically includes a combination of graphics and barcode elements, will be printed after the envelope has been filled, sealed and/or weighed. Consequently, the ability to print on an envelope, which may include inserts having staples, clips and/or other binding elements, is necessary, but nonetheless presents challenges in terms of the surface characteristics/conditions which yield optimum print quality.
A need therefore exists for a method and apparatus for printing on an irregular surface while maintaining print efficacy and readability.